SOLVED: Guest Additions screen resize causes strange behavior (strange to the point it's unusable)

Discussions about using Linux guests in VirtualBox.
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oceanjeremy
Posts: 9
Joined: 24. May 2020, 01:16

SOLVED: Guest Additions screen resize causes strange behavior (strange to the point it's unusable)

Post by oceanjeremy »

I've searched the forums here (and all over the web) and I'm getting the sinking feeling this problem is unique to my setup, because I'm not seeing my exact issue anywhere else. Super grateful to anyone who can take the time to help me out here.

Symptoms:
  • There are a lot, but the long and the short of it is that when I do get the guest screen resize working it only works correctly on my external monitor, and resizing will frequently send me back to the user login screen. Lots of flickering. And when the screen is very large (full screen or close to it) I can't click on anything — the guest machine doesn't identify any mouse action other than movement.
Critical info:
  • VirtualBox: Version 6.1.8 r137981 (Qt5.6.3)
  • Host: MacBook Pro / Catalina 10.15.4 / 13-inch / 64-bit / 8GB memory
  • External monitor: Acer - SA230 23" IPS LED FHD
  • Guest: CentOS 8 / kernel 4.18.0-147.8.1.el8_1.x86_64 / 2400GB memory
  • Guest Additions: Version 6.1.8
  • Logs are attached :wink:
In-depth description of the problem:
I installed my Guest Additions as per these instructions: https://www.tecmint.com/install-virtual ... el-fedora/

I knew something was off because — although my mouse was no longer captured, and could move freely between host and guest machine windows — I couldn't resize the screen. I could resize the window, leaving empty space around the CentOS Machine's display. Or I could scale it to larger sizes, but it would show pixellated, low-res, and the mouse pointer got really huge.

Some posts on this forum led me to try 1) setting "Maximum Guest Screen Size" to "None" and 2) changing "Graphics Controller" to "VBoxVGA."

If I do only one or the other of these things, nothing changes. If I do both of these things, I can resize my screen. But at what cost?

Firstly, when I select VBoxVGA (or VBoxSVGA, which also seems to work) I get a warning in the Settings screen that says "Invalid settings detected." If I click on it I get a message that says:
Display: Screen page:
The virtual machine is configured to use a graphics controller other than the recommended one (VMSVGA). Please consider switching unless you have a reason to keep the currently selected graphics controller.
So that bugs me a little bit, because if I set it to VMSVGA I can't resize my screen (and it's too small to work on).

But once I set Maximum Guest Screen Size to "None" and change Graphics Controller to VBoxVGA it's really no more usable. On either of my monitorsI can't get it larger than 80% of full screen without the mouse button becoming unresponsive. I'd like to use this mostly on my external monitor, but I'd like the flexibility of putting it in either. Whenever it's on my MacBook monitor it shrinks to 50% of the size. Then it frequently goes blank then flashes back to the CentOS user login screen, or will crash and become unresponsive. I can scale it to 200% then, but again if I get anywhere close to 80% of full screen the mouse button becomes unresponsive.

Worst of all, on either monitor the guest screen flickers frequently (usually every time I type any key — it becomes seizure-inducing when I enter a password).

Also worth noting: I thought I'd try "Enable 3D Acceleration," thinking that might at least fix the flickering. But whenever I check "Enable 3D Acceleration" it changes the Graphics Controller back to VMSVGA as soon as I click "OK." And then I can't resize my screen again. So 3D Acceleration is another dead end.

So what I'm left with is that I cannot use this guest machine without resizing the screen because it's too small to be functional.

And then when I get resizing to work I cannot use this guest machine because the screen flickers, and the mouse doesn't work when it's the size of a workspace that's actually workable for me.

So as of right now I can't use this guest machine at all.

Anyone have any idea what I can do to make this work for me?
Attachments
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Last edited by oceanjeremy on 27. May 2020, 00:02, edited 1 time in total.
fth0
Volunteer
Posts: 5668
Joined: 14. Feb 2019, 03:06
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Linux, Windows 10, ...
Location: Germany

Re: Guest Additions screen resize causes strange behavior (strange to the point it becomes unusable)

Post by fth0 »

You've written a very detailed report (so long that only few people will read it, BTW ;)). But there is one crucial thing that you didn't mention (else I overlooked it), and that is the amount of Video Memory provided to the VM, which is set to 16 MB according to the VBox.log file:

Change Settings > Display > Screen > Video Memory to 128 MB, Settings > Display > Screen > Graphics Controller to VMSVGA, enable Settings > Display > Screen > Acceleration: Enable 3D Acceleration, and try to reproduce your problems.
oceanjeremy
Posts: 9
Joined: 24. May 2020, 01:16

Re: Guest Additions screen resize causes strange behavior (strange to the point it becomes unusable)

Post by oceanjeremy »

Thanks fth0!

Is that why no one has responded, my post is too long? I've always been told I'm longwinded. :wink:

Right after I posted this I played around some more, and I set the Video Memory to 128 MB. Which didn't help at all.

I did do some more hunting and discovered this is a known bug in Guest Additions: There is a test build to fix the resizing issue (GA 6.1.9-138064 here: https://www.virtualbox.org/ticket/19590). But this one is still causing the X11 issue on guests using Xwayland instead of Xorg.

And of course my VM is using Xwayland.

I'm a total beginner on this: it's my first ever VirtualBox VM, and I'm only setting it up so I can take an online course in CentOS / RHEL. I'm pretty new to the Linux learning curve and have no idea how to switch from Xwayland to Xorg.

So I instead downgraded to Guest Additions 6.1.2 (https://download.virtualbox.org/virtualbox/6.1.2/). I guess I have to live with this until there's a new test build that fixes it on all fronts?

As for now, it runs realllly slowly on VMSVGA if I'm at the resolution I want to be at. VBoxVGA and VBoxSVGA give me too much flickering for it to be usable (and it won't let me select 3D Acceleration on either of them). So I've got it on VMSVGA and set the Video Memory to 128 MB, which helped some, and upped my VM machine to 4800 MB. Again, it helped some.

So now I'm just using it at a smaller resolution than I'd like, which will at least let me take this course I want to take.
oceanjeremy
Posts: 9
Joined: 24. May 2020, 01:16

Re: Guest Additions screen resize causes strange behavior (strange to the point it becomes unusable)

Post by oceanjeremy »

Got my answer!

Turns out Xwayland / Xorg is a real easy switch, and in CentSO you just have to change a setting in a .conf file and it defaults to Xorg from there on out. Don't even have to install anything.

So consider this thread SOLVED, steps are:
This is 100% fixed for me!
fth0
Volunteer
Posts: 5668
Joined: 14. Feb 2019, 03:06
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Linux, Windows 10, ...
Location: Germany

Re: Guest Additions screen resize causes strange behavior (strange to the point it becomes unusable)

Post by fth0 »

oceanjeremy wrote:Is that why no one has responded, my post is too long? I've always been told I'm longwinded. :wink:
Well, you were lucky, and now you get a longwinded answer back. ;)

First of all, these forums are looked after by volunteers in their spare time, so any reaction in less than 24 hours should be considered fast. Secondly, some volunteers answer many posts (to help many users) nearly every day, which means that they usually can only spend few minutes per post for reading and answering, and so they sometimes leave the longer posts for later. Those volunteers are the backbone of the forums and keep the forums alive. Thirdly, some volunteers (me included) only read and answer posts occasionally and then pick some posts they're interested in, which tend to be the longer ones.

Your initial post showed that you put a considerable effort in researching and describing your problem, so you well deserved a timely reaction. :)
oceanjeremy
Posts: 9
Joined: 24. May 2020, 01:16

Re: SOLVED: Guest Additions screen resize causes strange behavior (strange to the point it's unusabl

Post by oceanjeremy »

Thanks for the rundown — it's good to have a little bit of a primer on a forum's culture right out of the gates!

And thanks for being a long-form-reading volunteer. :D
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